Rice monoculture and integrated rice-fish farming in the Mekong Delta, Vietnam—economic and ecological considerations

Abstract

This study is a survey of agriculture practices and pest management strategies among rice and rice-fish farmers in the Mekong Delta. Based on an economic comparison between different farmer categories, it is argued that rice-fish farming provides a sustainable alternative to rice monoculture, if the farmer takes full advantage of the natural productivity of the rice field ecosystem. The aim should be to reduce the resource use, avoid overuse of agrochemicals and improve production efficiency through increased recycling of nutrients and matter. Integrated pest management (IPM) strategies should thus be adopted as a necessary complement to fish farming practices. IPM rice-fish farmers have the highest net income (19 500 000 VND per year ha⁻¹), due to comparatively low costs and high yields of both rice and fish. Also IPM rice-farmers have a high net income (18 400 000 VND per year ha⁻¹). Their productions cost are lower, but their rice yield is similar to that of non-IPM rice farmers. Non-IPM rice-fish farmers have the lowest net income (15 800 000 VND per year ha⁻¹) due to their high costs and low yields.

Introduction

Rice and aquatic products constitute a major part of the diet of the people in the Mekong Delta, Vietnam. Currently, some 17 million people live in this area, but the number is expected to increase up to 21 million by the year of 2010 (Sanh et al., 1998). This will lead to an increased demand for food in coming decades (Sanh et al., 1998). Nevertheless, there is a potential for an increase in agriculture production, which could, to some extent, satisfy the greater food demand, especially if integrated with aquaculture, as fish provide an important source of animal protein in the region (Duong et al., 1998, Sanh et al., 1998).

In the Mekong Delta, approximately 400 000 ha are suitable for freshwater aquaculture, but today less than 10% of the area is used for this purpose (Duong et al., 1998). To increase the production of fish, small-scale farmers are encouraged to take up integrated rice-fish production.

However, agriculture changes as a result of the green revolution have become a constraint for the development of integrated rice-fish farming (Cagauan and Arce, 1992, Dashu et al., 1992). With the introduction of high yielding, short duration rice varieties, the dominant pest control strategy has favoured chemical pesticides (Settle et al., 1996).

The increased reliance on pesticides in rice production has proved to be unsustainable and cost-ineffective due to pesticide-induced outbreaks of insect pests, development of pesticide resistant pests, rising costs of pesticide use, and the negative effects of pesticide use on human health and the environment. Prolonged misuse of pesticides, herbicides and fertilisers over the years has affected the development of inland fisheries, including rice-fish farming and aquaculture, negatively (Cagauan and Arce, 1992, Duong et al., 1998).

In an attempt to reduce pesticide use, important changes have taken place in strategic approaches to plant protection. Integrated Pest Management (IPM) methods have brought ecological principles and social science perspectives into traditional crop management. These ecologically based pest control methods have resulted in markedly improved rice farming systems, which are not only higher yielding but also more sustainable (Noda et al., 1998).

These methods have also improved the possibilities for adopting rice-fish farming, which provides a promising alternative for further developing ecological sound management strategies of the rice field environment (Dela Cruz, 1994, Cagauan, 1995, Halwarth, 1995, Halwarth, 1998). The introduction of fish into the paddy fields has been shown to reduce the need for pesticides, increase the farm household income and diversify agriculture production (Duong et al., 1998). Thus, it is believed that integrated farming systems can help farmers to increase their farm incomes and enhance sustainable agriculture and rural development (Duong et al., 1998).

This study is a survey of agriculture practices and pest management strategies among rice and rice-fish farmers in the Mekong Delta. The main objective of the study is to evaluate if integrated rice farming practices provide competitive alternatives to rice monocultures. Based on an economic comparison between different farming categories, it is argued that rice-fish farming can provide a sustainable alternative to rice monoculture, both from an economic as well as an ecological point of view. However, to achieve this it is important that the farmer take full advantage of the natural production capacity of the rice field ecosystem. Objectives such as sustainable utilisation of species and ecosystems, as well as the recognition and evaluation of the benefits derived from ecological processes and the life-supporting ecosystem, must play a significant part in the development of rice farming in the Mekong Delta (cf. Folke and Kautsky, 1992).

It is stressed in the paper that IPM strategies should be adopted as a necessary complement to integrated rice-fish farming practices and vice versa. Unwise use of pesticides may, for example, disrupt the ecological balance and decrease the yield of an integrated system. The knowledge gained from integrating rice with fish can, in turn, be used as a tool in IPM and thus serve as a vehicle to speed up the implementation of IPM strategies. A healthy environment is a prerequisite for successful fish farming, which should provide rice-fish farmers with strong incentives to adopt IPM strategies.